The objective of this work is to determine how glycogen synthase is regulated in muscle and other insulin-sensitive tissues. The proposed studies center around the role of glycogen synthase kinase in the inactivation (by phosphorylation) of glycogen synthase. We have recently discovered that most of the glycogen synthase kinase activity in most mammalian tissues is cyclic AMP-independent in contrast to the one which has previously been recognized (cyclic AMP-dependent protein kinase). Because these kinases differ in many important respects, the proposed studies will compare their effects on glycogen synthase and attempt to determine the physiological roles of each of these enzymes. Specifically we propose the following: 1) To purify and characterize the cyclic AMP-independent kinases and compare their properties to those of purified cyclic AMP-dependent protein kinase catalytic subunit. 2) To study the properties of glycogen synthase inactivated by each of these enzymes. 3) To attempt to identify metabolites and potential second messengers such as calcium which might regulate these kinases. 4) To determine the activity of glycogen synthase kinases and the kinetic properties of glycogen synthase formed in vivo under the influence of exercise, hormones and diet. Because the mechanisms by which glycogen synthase is regulated are only partly understood (particularly with reference to the action of insulin and alpha adrenergic agents) these studies should enhance our understanding of these mechanisms.